1. Field of the Invention
The present invention relates to a file management apparatus for managing electric files, in particular to a technology for managing time stamp addition performed on registered electric files.
2. Description of the Background Art
As electronic documents are increasingly used in many application domains, there are more occasions where evidence of an electronic document is required. For example, as evidence of an electronic document, a digital signature can be used to thereby provide assurance of the creator and authenticity of the document.
However, in order to use electronic documents in business transactions and applications, further evidence is required to prove that such an electronic document existed at a specific point of time. For this purpose, time stamp technology has been employed.
The procedures of time stamp addition and verification are specified in “RFC3161: Internet X.509 Public Key Infrastructure Time-Stamp Protocol (TSP).” Time stamp adding services conventionally provided in compliance with the specification ensure high reliability by adopting a system in which a certificate is obtained from a TA (Time Authority) and a CA (Certification Authority) that are third parties, and a stamp is added by a TSA (Time-Stamping Authority) at a time indicated by the TA.
The use of such time stamp technology allows for proving specifically that the data existed at the date and time when the time stamp was added (evidence of existence) and the data has not been tampered after the addition of the time stamp (evidence of integrity).
Not only for business transactions but also for various electronic documents that individuals and companies store in electronic form, providing strong evidence for these documents will be sought after in line with the enactment of the e-Document Law, the Personal Information Protection Act and the like. As a result, the use of time stamp adding services is expected to dramatically increase.
Conventional services of time stamp addition, however, has been run on a pay-as-you-go basis in which charges are made in proportion to the number of files to which time stamps are added. Accordingly, the usage increase of the services will lead to a cost increase.